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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Thermal surveillance of volcanoes of the Cascade Range utilizing ERTS DCP systems and imagery

The author has identified the following significant results. Successful installation of DCP sets at Mt. Baker volcano and at Mt. St. Helens volcano, Washington, completed the installation phase of experiment SR 251. Aerial IR scanner missions over the Cascade volcanoes were completed with a mission April 29th which provided thermographic IR images of Glacier Peak, Mt. Baker, Mt. St. Helens, Mt. Rainier, and Mt. Adams. Earlier repetitive coverage had obtained IR images depicting thermal anomalies of Lassen Volcanic National Park, Shasta, Crater Lake, and the northern Cascades. The April 29th mission and subsequent ground reconnaissance yielded new information on 48 heretofore unreported pinpoint radiation anomalies, of possible fumarolic origin, on the flanks of Mt. Rainier and several new thermal points on Mt. Baker. Cartographic plots of these anomalies, in conjunction with surface temperature and other data obtained as a result of experiment SR 251 will permit estimation of radiation heat loss during the repose periods of the host volcanoes.

Friedman, J. D.↗
NASA NTRS1973

Effect of solute interactions in columbium /Nb/ on creep strength

The creep strength of 17 ternary columbium (Nb)-base alloys was determined using an abbreviated measuring technique, and the results were analyzed to identify the contributions of solute interactions to creep strength. Isostrength creep diagrams and an interaction strengthening parameter, ST, were used to present and analyze data. It was shown that the isostrength creep diagram can be used to estimate the creep strength of untested alloys and to identify compositions with the most economical use of alloy elements. Positive values of ST were found for most alloys, showing that interaction strengthening makes an important contribution to the creep strength of these ternary alloys.

Klein, M. J.↗
NASA NTRS1973

Airborne profiling of ice thickness using a short pulse radar

This paper describes helicopter-borne measurements of ice thickness in Lake Superior, Lake St. Clair, and the St. Clair river as part of NASA's program to develop an ice information system. The profiler described is a high resolution, nonimaging, short pulse radar, operating at a carrier frequency of 2.7 GHz. The system can resolve reflective surfaces separated by as little as 10 cm and permits measurement of the distance between resolvable surfaces with an accuracy of about 1 cm. Data samples are given for measurements both in a static (helicopter hovering), and a traverse mode. Ground truth measurements taken by an ice auger team traveling with the helicopter are compared with the remotely sensed data and the accuracy of the profiler is discussed based on these measurements.

Vickers, R. S.↗
NASA NTRS1975

Surface friction of rock in terrestrial and simulated lunar environments

The conventional probe-on-the rotating-disk concept was used to determine the surface friction in mineral probe/specimen interfaces. Nine rocks or minerals and two stainless steels were tested in both new (NT) and same track (ST) tests under three different pressure environments-atmospheric, UHV, and dry nitrogen. Each environment was further subdivided into two testing conditions, that is, ambient and elevated (135 C) temperatures. In NT tests, friction was the lowest in an atmospheric pressure condition for all rock types and increased to the largest in UHV ambient condition except for pyroxene and stainless steel. Friction values measured in dry nitrogen ambient condition lie between the two extremes. Heating tends to increase friction in atmospheric and dry nitrogen environment but decreases in UHV environment with the exception of stainless steel, basalt, and pyroxene. In ST tests, friction was the lowest in the first run and increased in subsequent runs except for stainless steel where the reverse was true. The increases leveled off after a few runs ranging from the second to the seventh depending on rock types.

Roepke, W. W.↗
NASA NTRS1977

Large, high resolution integrating TV sensor for astronomical appliations

A magnetically focused SEC tube developed for photometric applications is described. Efforts to design a 70 mm version of the tube which meets the ST f/24 camera requirements of the space telescope are discussed. The photometric accuracy of the 70 mm tube is executed to equal that of the previously developed 35 mm tube. The tube meets the criterion of 50 percent response at 20 cycles/mm in the central region of the format, and, with the removal of the remaining magnetic parts, this spatial frequency is expected over almost all of the format. Since the ST f/24 camera requires sensitivity in the red as well as the ultraviolet and visible spectra, attempts were made to develop tubes with this ability. It was found that it may be necessary to choose between red and u.v. sensitivity and tradeoff red sensitivity for low background. Results of environmental tests indicate no substantive problems in utilizing it in a flight camera system that will meet the space shuttle launch requirements.

Spitzer, L. J.↗
NASA NTRS1978

Surface acoustic wave stabilized oscillators: Additional aging results

Updated aging data for SAW oscillators with aluminum transducers on ST-cut quartz, for gold transducers on ST-cut quartz, and for aluminum transducers on SiO2/LiTaO3. Devices with gold transducers age differently (both and shape of curve) from those having a aluminum transducers indicating the transducer metallization can represent an important aging mechanism.

Source record↗
NASA NTRS1979

Wide field/planetary camera optics study

Design feasibility of the baseline optical design concept was established for the wide field/planetary camera (WF/PC) and will be used with the space telescope (ST) to obtain high angular resolution astronomical information over a wide field. The design concept employs internal optics to relay the ST image to a CCD detector system. Optical design performance predictions, sensitivity and tolerance analyses, manufacturability of the optical components, and acceptance testing of the two mirror Cassegrain relays are discussed.

Source record↗
NASA NTRS1979

The space telescope observatory

A guide to the expected characteristics of the space telescope (ST) observatory is presented. The general objectives of the ST observatory are summarized. The plans for the development of the observatory are described with a brief history of the scientific activities; an account of the scope of the present program; a summary of the major responsibilities of the contractors; and a list of the project milestones are included. The performance characteristics of the observatory are provided including the imaging and stray light characteristics, pointing capability, and operational access. The expected performance characteristics of all six of the first generation science instruments are summarized. The mode of operations is described which includes a discussion of program options, guide star selection, methods of acquisition, and quick look data capabilities.

Bahcall, J. N.↗
NASA NTRS1979

Investigation of small solar system objects with the space telescope

The application of the space telescope (ST) to study small objects in the solar system in order to understand the birth and the early evolution of the solar system is discussed. The upper size limit of the small bodies is defined as approximately 5000 km and includes planetary satellites, planetary rings, asteroids, and comets.The use of the astronomical instruments aboard the ST, such as the faint object camera, ultraviolet and infrared spectrometers, and spectrophotometers, to study the small solar system objects is discussed.

Morrison, D.↗
NASA NTRS1979

Galactic evolution with the space telescope

Some aspects of research on galactic evolution with the Space Telescope (ST) are discussed. Viewpoints are provided from which ST (and related ground based) studies can be planned.

Tinsley, B. M.↗
NASA NTRS1980

Remote estimation of the surface characteristics and energy balance over an urban-rural area and the effects of surface heat flux on plume spread and concentration

A one dimensional boundary layer model was used in conjunction with satellite derived infrared surface temperatures to deduce values of moisture availability, thermal inertia, heat and evaporative fluxes. The Penn State satellite image display system, a sophisticated image display facility, was used to remotely sense these various parameters for three cases: St. Louis, Missouri; the Land Between the Lakes, Kentucky; and Clarksville, Tennessee. The urban centers displayed the maximum daytime surface temperatures which correspond to the minimum values of moisture availability. The urban center of St. Louis and the bodies of water displayed the maximum nighttime surface temperatures which correspond to the maximum thermal inertia values. It is shown that moisture availability and thermal inertia are very much responsible for the formation of important temperature variations over the urban rural complex.

Dicristofaro, D. C.↗
NASA NTRS1981

Test of charge injection device, phase 1

A computer-controlled automatic facility containing two interactive microprocessors, peripherals, and an optical bench was used to obtain device characteristics for use in evaluating CID's as the sensor element in a prospective star tracker application. Each of the ST-256 chips tested contains a 256 x 256 pixel element array with 65536 picture elements. Two ST-256 devices were tested at 20 C under light levels of 10%, 0.1%, and 0.01% saturation, and in darkness. The saturation level was established at 0.95 microwatts sq cm as measured by the radiometeric sensor. Two test runs under each condition were performed for each chip. Two complete sets of data for each of the devices were thus obtained. A separate data field was used to store the results of each test condition. Repetitive runs of a test condition were stored sequentially in the same file. Examination of the data using print-outs is shown in examples.

Gradinger, A.↗
NASA NTRS1981

A study of model parameters associated with the urban climate using HCMM data

Infrared and visible data from the Heat Capacity Mapping Mission (HCMM) satellite were used to study the intensity of the urban heat island, commonly defined as the temperature difference between the center of the city and the surrounding suburban and rural regions, as a function of changes in the season and changes in meteorological conditions in order to derive various parameters which may be used in numerical models for urban climate. The analysis was focused on the city of St. Louis; and in situ data from St. Louis was combined with HCMM data in order to derive the various parameters. The HCMM data were mapped onto a Mercator projection map of the city and ground temperatures were established using data corrected for the effects of atmospheric absorption. The corrected and uncorrected HCMM data were compared to determine the magnitude of the error induced by atmospheric effects.

Source record↗
NASA NTRS1982

Fabrication of Essex EVA ratchet wrenches

The extravehicular activity (EVA) ratchet wrench was developed. Shortly after Space Telescope (ST) maintenance simulations began, the need for a specialized maintenance tool arose. With inputs of tool requirements and design recommendations, several development model wrenches were tested in conjunction with ST neutral buoyancy simulations. The wrench design was modified and refined.

Vanvalkenburgh, C. N.↗
NASA NTRS1982

Volcanoes and climate

The evidence that volcanic eruptions affect climate is reviewed. Single explosive volcanic eruptions cool the surface by about 0.3 C and warm the stratosphere by several degrees. Although these changes are of small magnitude, there have been several years in which these hemispheric average temperature changes were accompanied by severely abnormal weather. An example is 1816, the "year without summer" which followed the 1815 eruption of Tambora. In addition to statistical correlations between volcanoes and climate, a good theoretical understanding exists. The magnitude of the climatic changes anticipated following volcanic explosions agrees well with the observations. Volcanoes affect climate because volcanic particles in the atmosphere upset the balance between solar energy absorbed by the Earth and infrared energy emitted by the Earth. These interactions can be observed. The most important ejecta from volcanoes is not volcanic ash but sulfur dioxide which converts into sulfuric acid droplets in the stratosphere. For an eruption with its explosive magnitude, Mount St. Helens injected surprisingly little sulfur into the stratosphere. The amount of sulfuric acid formed is much smaller than that observed following significant eruptions and is too small to create major climatic shifts. However, the Mount St. Helens eruption has provided an opportunity to measure many properties of volcanic debris not previously measured and has therefore been of significant value in improving our knowledge of the relations between volcanic activity and climate.

Toon, O. B.↗
NASA NTRS1982

Magnetic field compression at the dayside magnetopause

The degree of compression sustained by the solar wind field as it convects to the magnetopause has been determined empirically with magnetometer data from ISEE 3 in the solar wind and ISEE 1 in the magnetosheath. At the stagnation point, the strength B(SH) of the magnetosheath field may be expressed as B(SH) = square root of 4 X B(SW)' X B(ST), which implies that B(SH) is equal to the geometric mean of the stagnation field strength B(ST) and the shocked solar wind field, approximated by 4 X B(SW)'. For the usual spiral wind pattern of the solar wind field, B(SH) on the duskside of the magnetopause is about 20 percent stronger than it is on the downside. No dependence of B(SH) on the sign of the north-south component of the solar wind field is apparent.

Crooker, N. U.↗
NASA NTRS1983

Satellite drag prediction effects on Shuttle mission planning

Long-term factors, along with Shuttle performance limitations, are considered in order to illustrate the need for more reliable long-term drag (meaning 'solar cycle') prediction techniques. Such techniques would make it possible to confidently plan dual-objective Shuttle flights, which maximize Shuttle cargo loadings and thus reduce costs. In describing the coupled mission concept, it is pointed out that by deploying one payload while retrieving or servicing another, the Space Transportation System can maximize the usefulness of the Shuttle and reduce the cost per customer. It is shown here that the proposed mission coupling LDEF (Long Duration Exposure Facility) with ST (Space Telescope) must be rejected since the Shuttle performance limitations prohibit deployment of the ST at even 315 n mi with a subsequent LDEF retrieval. If, however, it were possible to predict solar cycles, then, depending on the prediction, a mission of this type could be feasible.

Young, K. A.↗
NASA NTRS1983

Production of O(-) from CO2 by dissociative electron attachment

Dissociative electron attachment cross-section measurements for the production of O(-) from CO2 are performed using a crossed target-beam - electron-beam collision geometry and a quadrupole mass spectrometer. The relative flow technique is used in determining the absolute values of the cross sections. The attachment energies corresponding to the five cross-section maxima are given. They are 4.4 + or - 0.1, 8.2 + or - 0.1, 13.0 + or - 0.2, 16.9 + or - 0.2, and 19.4 + or 0.2 eV. Also given are the cross sections at these maxima: 1.43 x 10 to the -19th sq cm, 4.48 x 10 to the -19th sq cm, 8.1 x 10 to the -21st sq cm, 8.1 x 10 to the -21st sq cm, and 1.2 x 10 to the -20th sq cm, respectively.

Orient, O. J.↗